Change gitpod button to HTML link

This is a workaround to skip the automatic "external" icon appended to normal
links in docs MD.

content/docs/user-guide/contributing/docs.md

@@ -63,7 +63,9 @@ formatted and linted as well, which is also ensured by the full setup below.
 > dependencies, run `yarn build`, and start the webserver so that you can start
 > straight away:
 
-[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/iterative/dvc.org)
+<a href="https://gitpod.io/#https://github.com/iterative/dvc.org">
+  <img src="https://gitpod.io/button/open-in-gitpod.svg" alt="Open in Gitpod">
+</a>
 
 Make sure you have a recent LTS version of [Node.js](https://nodejs.org/en/)
 (`>=12.0.0`), and install [Yarn](https://yarnpkg.com/):